Generally, as the particle size of fine particles decreases (to less than 10 .mu.m in diameter), their agglomerating force becomes greater, with a plurality of particles sticking together to form an agglomerated particle which tends to behave as a coarse particle. Heretofore, a system using an ordinary orifice with a single hole or an ejector has been employed as an agglomerated particle dispersing device. With such conventional dispersing device, however, only a small amount of fine particles can be treated, thus an obstacle occurs to development of a large-sized classifier or a reactor of large capacity handling a large amount of fine particles.
According to the conventional single hole type dispersing device described above, when it is desired to increase the amount to be treated, the aperture diameter has to be increased, so that sufficient dispersion cannot be attained unless excessive power is applied. That is, the amount that can be treated by the state-of-the-art dispersing device for dispersing single particles having diameters of less than a few .mu.m is limited (at the present stage; 30-50 kg/hr/unit).